A recent study found that high school seniors who use synthetic cannabinoids are more likely to use other drugs when compared with students who only use cannabis. 

Synthetic cannabinoids, or synthetic cannabinoid receptor agonists, bind to the same receptors as cannabis. Currently, there are 14 families of synthetic cannabinoids, all of which have very different chemical structures. Although they bind in the same places as cannabis, their effects can vary widely — as can their safety.

As these novel chemicals are designed and consequently banned, new versions are created to take their place. Worryingly, as they evolve, some fear that they are becoming more potent.

Synthetic cannabinoids — which are sold under names such as K2 and Spice — are marketed as having similar effects to marijuana, but they can be many times more potent.

They are often sprayed onto plant matter and sold as "herbal incense," or they may be labeled "not for human consumption" and marketed as "legal" marijuana. Sometimes, they are even sold as "research chemicals."